Damascus, Syria - A year ago, Ali was enjoying university in Damascus, looking forward to a career in dentistry and paying little heed to politics in a country controlled by a single family for over 40 years.

That all changed, not so much when other Syrians took to the streets to demand President Bashar al-Assad step down, but when a mysterious message popped up on his Facebook page; it told him to get out of town, or die - because he was the wrong religion.

"You Alawite," read a text on the social networking site, widely hailed by pro-democracy activists for enabling the Arab Spring uprisings. "We don't want to see your face in Barzeh."

Now, long dormant religious bigotries have thrust politics on Ali, who was born into the minority Alawite sect and still lives in the Damascus suburb of Barzeh, where most of his neighbours are Sunni Muslims. The 25-year-old student is now a firm supporter of Assad, not from any admiration for the wealthy elite that has run the country with an iron - and often bloody - fist for four decades, but because they too are Alawites.

"They sent me the threat just because I am an Alawite living in Barzeh," Ali said during a series of interviews Reuters conducted in the Syrian capital last week with a variety of Alawite residents who asked that their identities be concealed.

If Assad falls, they fear a bloodbath for fellow Alawites, outnumbered six to one by the Sunnis in a Syrian population of 23 million, which also includes large minorities of Christians and ethic Kurds.

"We will go to the palace to protect him with our lives," said Mahmoud, an Alawite student at another Damascus university, who spoke to Reuters among a group of friends.

"If Assad goes," added another in the group, also called Ali, "I'm sure I'll either end up dead or I'll leave the country."

ANGER AT CRACKDOWN

Opposition leaders, some of whom have taken up arms in an increasingly violent confrontation that has killed more than 5,000 people in 11 months, mostly dismiss suggestions the revolt is destined to divide Syrians along ethnic and religious lines.

But millions are incensed by the killing, arrests and torture unleashed last year by the Alawite-led authorities against demonstrators, including women and children, who confronted them in mainly Sunni cities like Deraa.

In a country which has seen refugees stream in from the sectarian blood-letting in Iraq in recent years, and where Assad and his late father are widely perceived by much of the 75-percent Sunni majority to have heavily favoured the once scorned Alawites, the language of religious hatred is growing louder. Stories of reciprocal atrocity are gaining currency.

Typical of such tales is that of Ali, the dental student. He said he took the threat on Facebook seriously because one of his uncles had been killed. His body parts were delivered in a bag to his home village in the Alawites' western mountain heartland.

Mahmoud, who hails originally from Rabia in rural Hama province, said 39 people from his village had been killed since March: "If someone leaves the village, is stopped at a checkpoint and they know he is an Alawite, they kill him."

Like accounts from Homs last month of a massacre of 14 members of a Sunni family by suspected pro-government Alawite militiamen, or 'shabbiha', the report is impossible to check in a country where reporting is heavily restricted.

For the Alawites, who identify their faith as a variant of the Shi'ite Islam practised in Iran, long a close ally of Assad, the rise in the ranks of the opposition of the Sunni Islamist movement the Muslim Brotherhood and other conservative Sunnis who accuse Alawites of heresy is a particular cause of anxiety.

"If Bashar loses power, then definitely a non-Alawite will rule," said Fadi, a harassed-looking man in his 30s who runs a clothes store in Damascus. "The new regime will be tough on us Alawites and it will discriminate against us."

Fadi admitted that some of his acquaintances had put their resistance to change into action, driven by fear to attack and beat up some of the demonstrators who have dared to protest against Assad and his Alawite-dominated security forces.

Others are just keeping their heads down, trying to conceal any sign of their affiliations. That can range from accent - many Alawites hail from mountain villages near Lebanon whose Arabic is distinctive - to their names, since some given names are more common among either Alawites or Sunnis.

"These days I am scared to give my name," said Ali, the student from the mainly Sunni suburb of Barzeh. "Sometimes I say it is Omar. Sometimes I use something else."

HISTORICAL GRIEVANCES

Communal support for Assad invokes not only the fear of reprisal, but the historic marginalisation of Alawites from the centuries of Sunni Ottoman rule down to the emergence of Assad's father, Hafez al-Assad. He took power in 1970 and died in 2000.

Before the Assads, Alawites say, they were treated routinely as second-class citizens, discriminated against and deprived of holding senior posts in the government.

"My father used to walk 20 km to get to school, because schools in our area were scarce," said Abdullah, a government employee in Damascus recalling his father's childhood in the Alawite mountain villages in the 1950s and 60s. "Now we're allowed proper education, and this is thanks to Hafez."

Assad's opponents, for their part, recount decades of fear and oppression under the Assads, not just for Sunni Islamists but secular liberals, communists, Kurds and pretty much anyone who dared question the family's monopoly on power.

Islamists take their historical bearings from the bloodiest moment of Assad rule when, 30 years ago this week, the father unleashed his forces, with Alawites at the spearhead, on Hama.

At least 10,000 people were killed, possibly two or three times as many, as artillery and tanks pounded the stronghold of the rebellious Muslim Brotherhood, levelling much of the old city in the process. It is an experience some Syrian Islamists recount as the profanation of sacred territory by heretics.

Adnan Arour, a Sunni cleric who fled Syria during Assad's reprisals against the Brotherhood, now wages a campaign of sectarian invective against the younger Assad from Sunni-led Saudi Arabia - which has backed calls for the end of his rule.

"As for those Alawites who violate what is sacred, when the Muslims rule and are the majority of 85 percent, we will chop you up and feed you to the dogs," Arour said in June.

Though he does not speak for a majority in Syria, for fundamentalist Sunnis, Alawites' beliefs and practices place them outside the bounds of Islam altogether.

ALAWITES' DEFENCE

Alawites dominate senior positions in the security apparatus. But many others say they see few of the privileges that have accrued to Assad's inner circle over four decades.

Many of the two million or so Alawites live still in rural villages, while those who have migrated to Damascus say they are no better off than the substantial Sunni middle class which has also so far generally stood behind Assad and against upheaval.

Yara, a government employee in her 30s, was, like many Alawites, at pains to stress that their community did not feel especially favoured under the Assads and that, in her view, Sunnis benefited more from public sector employment: "Most of us Alawites are small traders," she told Reuters in the capital.

"The Sunnis get the government jobs, so we don't get our due from the state," said Yara, who was sporting a bracelet adorned with the red, black and white Syrian flag adopted after Assad's Baath Party seized power in the 1960s. It stands in contrast to the older green, black and white tricolour used by opponents.

"The Alawites live in the mountains, with no electricity or water," Yara said of the continuing hardships for many of her community. "And now they say we should be kicked out?"

Though many Syrians would scoff at the notion, other Alawites insist that the president is a secular leader, blind to sectarian concerns, whose wife is Sunni.

As well as sharpening sectarian frictions, the violence of recent months has opened up differences within the Alawite community. Some prominent Alawite political activists have taken a stand against Assad. Aref Dalila and Najati Tayara have both been jailed for their opposition, while noted actress Fadwa Suleiman has led protests in the opposition stronghold of Homs.

But the Alawite students who spoke in Damascus dismissed them as self-serving attention-seekers, careless of the threat facing the minority as a group. "They don't represent us," said the student Mahmoud. "They're just hypocrites looking for fame."

Some also call naive those Alawites who push for reform, citing the example of Egypt's Christian minority, who embraced the revolution in Cairo alongside their Muslim compatriots but now fear a new rule dominated by conservative Sunnis.

"ALL MURDERERS"

At bottom, Mahmoud and other Syrian Alawites argue, it will not matter whether an individual opposes Assad or not - in the final accounting, if he is overthrown by a movement dominated by Sunni Islamists, all Alawites will be marked for revenge.

As one opposition activist put it in a private conversation recently: "Every Alawite between the age of 16 to 40 is a murderer, whether he likes it or not.

"The regime has recruited them, either as shabbiha in the capital or in the regular army, to kill us."

Disdain for the Alawites as a group is not limited to the firebrand preachers broadcasting from the Gulf. At a polite, middle-class dinner party last week in Damascus, one educated professional, a Sunni though not a pious one, spoke with casual disparagement that betrays each sect's ignorance of the other.

"The Alawites do not have mosques," the man said. "They do not pray like us. Nobody knows what they are."

The prospect of life without the Assads - a prospect many world and Arab leaders see as all but inevitable - is driving many Alawites to desperate extremes. Rallies in support of the president and his family were, in the early days of the rising, relatively staid affairs, where loyalists bussed in from Alawite strongholds ran through a routine playlist of Baathist chanting.

Now, there is real anger, passion and fear on the streets, with some crowds howling devotion to the president's younger brother Maher, commander of a military unit in the vanguard of the crackdown on opposition bastions.

Screaming for him to "finish off" the rebels, demonstrators have chanted: "Get on with it, Maher. For God's sake!"

Mahmoud, the Damascus student from Rabia, was keeping his calm when he spoke to a foreign reporter. But his voice betrayed a grim determination that sends a chilling signal for Syria's future: "For me, it's an eye for an eye," he said.

"If someone wants to kill me and my family I won't just stand and watch. If this is how they want it, then so be it."